# Efficient way to catch & continue on exception **URL:** \ **Category:** ruby-talk\ **Created:** [19 October 2011 18:49 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897 "2011-10-19T18:49:45Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Kassym\_Dorsel](https://avatars.discourse-cdn.com/v4/letter/k/5fc32e/32.png) [@Kassym\_Dorsel](https://rubytalk.org/u/Kassym_Dorsel)\ **Post date:** [19 October 2011 18:49 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/1 "2011-10-19T18:49:45Z")
I have the following : hs = {} hs.default = nil hs['name3'] = command3 hs['name2'] = command2 hs['name1'] = command1 Where command\* are methods that can fail and raise an exception. The only way I know to deal with this is : begin hs['name3'] = command3 rescue end begin hs['name2'] = command2 rescue end begin hs['name1'] = command1 rescue end Is there a more compact/nicer of dealing with this. Because I have about 10-15 of these in a row in my code that I unfortunately can't change to anything better. What I would really want is something that if an exception is raised to skip that line and just continue with the next line. > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Steve\_Klabnik](https://avatars.discourse-cdn.com/v4/letter/s/0ea827/32.png) [@Steve\_Klabnik](https://rubytalk.org/u/Steve_Klabnik)\ **Post date:** [19 October 2011 19:04 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/2 "2011-10-19T19:04:41Z")
rbx-head :001 \> def throw rbx-head :002?\> throw "hey" rbx-head :003?\> end =\> #\ rbx-head :004 \> throw rescue puts "rescued" rescued =\> nil ---
**Author:** ![Carina\_C\_Zona](https://avatars.discourse-cdn.com/v4/letter/c/ea5d25/32.png) [@Carina\_C\_Zona](https://rubytalk.org/u/Carina_C_Zona)\ **Post date:** [19 October 2011 19:14 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/3 "2011-10-19T19:14:05Z")
> > **···** > > On Wed, Oct 19, 2011 at 11:49 AM, Kassym Dorsel \ wrote: > > > begin > > hs['name3'] = command3 > > rescue > > end > > begin > > hs['name2'] = command2 > > rescue > > end > > begin > > hs['name1'] = command1 > > rescue > > end > > > > Is there a more compact/nicer of dealing with this. Because I have about > > 10-15 of these in a row > > -- > Carina ---
**Author:** ![Kassym\_Dorsel](https://avatars.discourse-cdn.com/v4/letter/k/5fc32e/32.png) [@Kassym\_Dorsel](https://rubytalk.org/u/Kassym_Dorsel)\ **Post date:** [19 October 2011 20:38 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/4 "2011-10-19T20:38:59Z")
That could work. Just one last thing to solve. assignments = {:name1=\>"arr.grep(/Input:.\*/)[0][6..-1]"} assignments.each\_pair {|k,v| hs[k] = how do I call this command associated with :name1} .method(:method).call(arguments) and .send("method") only seem to work for single methods and not combined ones like the example above. > **···** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Gary\_Wright](https://avatars.discourse-cdn.com/v4/letter/g/58956e/32.png) [@Gary\_Wright](https://rubytalk.org/u/Gary_Wright)\ **Post date:** [19 October 2011 23:41 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/5 "2011-10-19T23:41:24Z")
A couple options: hs = {} hs['name3'] = (command3 rescue nil) hs['name2'] = (command2 rescue nil) hs['name1'] = (command1 rescue nil) Or how about: module Capture   def capture(key)     self[key] = yield   rescue     self[key] = nil   end end hs = {}.extend Capture hs.capture('name3') { command3 } hs.capture('name2') { command2 } hs.capture('name1') { command1 } > **···** > > On Oct 19, 2011, at 2:49 PM, Kassym Dorsel wrote: > > > I have the following : > > > > hs = {} > > hs.default = nil > > hs['name3'] = command3 > > hs['name2'] = command2 > > hs['name1'] = command1 > > > > Where command\* are methods that can fail and raise an exception. The > > only way I know to deal with this is : ---
**Author:** ![Kassym\_Dorsel](https://avatars.discourse-cdn.com/v4/letter/k/5fc32e/32.png) [@Kassym\_Dorsel](https://rubytalk.org/u/Kassym_Dorsel)\ **Post date:** [19 October 2011 19:45 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/6 "2011-10-19T19:45:46Z")
C. Zona wrote in post #1027457: > > Something like that, but I can't use a loop. Each command and each hash entry name is different and have to be hard coded. > **···** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Sam\_Duncan](https://avatars.discourse-cdn.com/v4/letter/s/b9bd4f/32.png) [@Sam\_Duncan](https://rubytalk.org/u/Sam_Duncan)\ **Post date:** [19 October 2011 21:46 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/7 "2011-10-19T21:46:03Z")
Well, you can do this, but remember you have to deal with exceptions thrown in your proc. ruby-1.9.2-p290 :001 \> hs = {}   =\> {} ruby-1.9.2-p290 :002 \> target =   =\> ruby-1.9.2-p290 :003 \> assignments = {:name1=\>Proc.new {|arr| foo = arr.grep(/Input:.\*/)[0]; foo && foo[6..-1] || nil}}   =\> {:name1=\>#\} ruby-1.9.2-p290 :004 \> assignments.each\_pair {|k,v| hs[k] = v.call(target)}   =\> {:name1=\>#\} ruby-1.9.2-p290 :005 \> hs   =\> {:name1=\>nil} The proc in assignments could be something like this if you didn't want the foo (you can use tap or something to debug inside the proc if needs be) ruby-1.9.2-p290 :006 \> assignments = {:name1=\>Proc.new {|arr| arr.grep(/Input:.\*/)[0][6..-1] rescue nil}} =\> {:name1=\>#\} ruby-1.9.2-p290 :007 \> assignments.each\_pair {|k,v| hs[k] = v.call(target)}   =\> {:name1=\>#\} ruby-1.9.2-p290 :008 \> hs   =\> {:name1=\>nil} Does that help? Sam > **···** > > On 20/10/11 09:38, Kassym Dorsel wrote: > > > That could work. Just one last thing to solve. > > > > assignments = {:name1=\>"arr.grep(/Input:.\*/)[0][6..-1]"} > > > > assignments.each\_pair {|k,v| hs[k] = how do I call this command > > associated with :name1} > > > >   .method(:method).call(arguments) and .send("method") only seem to work > > for single methods and not combined ones like the example above. ---
**Author:** ![Sam\_Duncan](https://avatars.discourse-cdn.com/v4/letter/s/b9bd4f/32.png) [@Sam\_Duncan](https://rubytalk.org/u/Sam_Duncan)\ **Post date:** [19 October 2011 20:05 UTC](https://rubytalk.org/t/efficient-way-to-catch-continue-on-exception/63897/8 "2011-10-19T20:05:28Z")
> C. Zona wrote in post #1027457: > [Ruby: Continue a loop after catching an exception - Stack Overflow](http://stackoverflow.com/questions/2624835/ruby-continue-a-loop-after-catching-an-exception) > > Something like that, but I can't use a loop. Each command and each hash > entry name is different and have to be hard coded. Do they need to be hard coded? Can you configure it with a hash of name to command mapping, and then simply iterate the hash with each\_pair? \> irb ruby-1.9.2-p290 :001 \> hs = {}   =\> {} ruby-1.9.2-p290 :002 \> hs.default = nil   =\> nil ruby-1.9.2-p290 :003 \> def command1; 'command1\_result';end   =\> nil ruby-1.9.2-p290 :004 \> def command2; 'command2\_result';end   =\> nil ruby-1.9.2-p290 :005 \> def command3; 'command3\_result';end   =\> nil ruby-1.9.2-p290 :006 \> assignments = {:name1=\>:command1, :name2=\>:command2, :name3=\>:command3}   =\> {:name1=\>:command1, :name2=\>:command2, :name3=\>:command3} ruby-1.9.2-p290 :007 \> assignments.each\_pair {|k,v| hs[k] = method(v).call}   =\> {:name1=\>:command1, :name2=\>:command2, :name3=\>:command3} ruby-1.9.2-p290 :008 \> hs   =\> {:name1=\>"command1\_result", :name2=\>"command2\_result", :name3=\>"command3\_result"} Then you have your loop. Sam > **···** > > On 20/10/11 08:45, Kassym Dorsel wrote: